Communication networks consist of a variety of hardware equipment and software and are increasing in use and complexity. The popularity of communication networks and the growth in the amount of data transferred between network users has forced the capacity of networks and protocols to increase with time. A variety of network communication protocols transfer data between devices coupled by a network. Ethernet and Asynchronous Transfer Mode are examples of such communication protocols.
Asynchronous Transfer Mode ("ATM", hereafter) provides bandwidths as low as 25 megabits/second using twisted cables and as high as 10 gigabits/second using optical cables. An ATM switch transfers cells between various points in a network. A cell contains control information, a header, and a data packet. The header within the cell contains switching identifiers enabling the ATM switch to route the data. The ATM switch interrogates each switching identifier it receives against a programmed list to determine which output channel the cell should be output. When the data packets are received by the intermediate node, destination information is contained in header which accompanies the data packet. The node determines whether it has previously agreed to route the data packets for that transmission by examining its memory to determine whether the destination information has previously been stored. If it has, a forwarding address has also been stored and the node forwards the data packet to the next node in the route toward the destination address.
The wide range of communications networks naturally results in a need for a wide variety of hardware. A first, brute force, method of supporting each network configuration is to design and manufacture an individual hardware solution for each possible application. Although such a product portfolio is very capable, it is also expensive to develop and maintain. A second method of supporting a wide variety of situations is to develop a single hardware product designed to meet the requirements of the most demanding application. For instance, a manufacturer might design a single ATM switch that operates at the highest expected bandwidth. Every user who needed less capacity than the most demanding application would simply not use the bandwidth. Typically, such a strategy involves hidden costs to either the manufacture or to the end user.